Direction: Make these sentences more concise by changing negatives to positives and by clearing out clutter words and needless qualifiers. 1. I am not unappreciative of your help. 2. Do not accept a check that is not signed. 3. Our design must avoid nonconformity with building codes. 4. Never fail to wear protective clothing in the radioactive laboratory. 5. The machine will not function until the power is turned on. 6. It 's not unlikely that there will be many occurrences of this mistake. 7. It ’s not unusual to find many complex sentences of this sort in professional journals. 8. The problem of river pollution will not be solved unless the chemical factory in the upper stream is shutdown or removed.